


eternal love.

by heroicgay



Category: Shadowhunters (TV)
Genre: 3x22 continuation, Canon Compliant, Fluff, Immortality, M/M, Soft Husbands, i love the lightwood-banes
Language: English
Status: Completed
Published: 2019-06-19
Updated: 2019-06-19
Packaged: 2020-05-15 00:36:30
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,125
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19284487
Author URL: https://archiveofourown.org/users/heroicgay/pseuds/heroicgay
Summary: “Do you remember how Clary left letters before she…?” Alec sighed. Sure, they weren’t the closest, but she was still a friend and it wasn’t an easy thing for him to discuss.“Forgot about all of us?” Magnus finished with a bitter huff. He’d spent countless nights cursing the angels for making him lose yet another friend. And twice, at that.Alec swallowed down the lump in his throat and nodded. “Yeah. Well, she left a little something extra with mine. A gift. I wanted to tell you about it so many times but every moment just felt wrong or insensitive, all things considered.”“What kind of gift?” Magnus inquired curiously.





	eternal love.

**Author's Note:**

> i’ve been sitting on this idea since the finale aired and after sharing my headcanon with my twitter followers, i was basically begged to write it, so here is me finally bringing it to life! enjoy!

          “How is the High Warlock of Alicante?” Alec asked, his lips curling up into a proud smile as the title rolled off his tongue. Magnus had been given the job just a few short months after their marriage as repayment for essentially saving their world (not to mention the countless other favors he’d done for the Shadowhunters). It was a groundbreaking, historical change for sure, and nobody else was better suited or more deserving of the position.

“Mm, much better now that you’re here,” Magnus confessed earnestly as he continued to jot down the details of the appointment he’d just booked.

Alec let out a quiet, fond laugh while his heart skipped a beat in his chest. No matter how long they were together, there was no way he’d ever get used to this.

“Thirsty?” He quirked a brow despite the fact that Magnus’ attention was elsewhere.

That had Magnus peeking up at him with a relaxed smile. “You read my mind.”

He gave a brief nod before walking over to the drink cart, preparing two martinis. His mind had begun to wander a bit but the sound of a phone vibrating instantly pulled him back. He glanced towards the coffee table with pursed lips.

“Busier than ever, I see.”

Magnus reached over and silenced the phone.

“It’s been ringing off the hook like that all day,” He sighed, going a bit tense as if the stress had just fully caught up with him. When Alec approached with drinks in hand, though, he relaxed once more.

“But, I have much better things to do,” He added and then carelessly tossed both his book and pen to floor before accepting the martini.

Alec smiled in that sweet, adoring way reserved just for his husband, then held out his glass in a toast.

“To us.”

“To us,” Magnus echoed with a pleasant expression as they clinked their glasses together and began to drink.

In the silence as they finished off their beverages, Alec’s mind had started to wander again.

Their first wedding anniversary had passed about a week ago and although they celebrated, it wasn’t entirely the joyous occasion they’d hoped for considering it was also the anniversary of the angels cursing Clary to life as a mundane with no recollection of the Shadow World. As a result, it wasn’t the best time for Alec’s gift to Magnus (though technically, it was a gift from Clary to the both of them) due to the somberness lingering in the air. Since then, he’d been anxiously waiting for the perfect moment. It was harder to find than expected. Their new positions in the Shadow World kept them fairly busy and often left them too exhausted to do much of anything afterwards, however Alec’s patience was starting to wear thin. Every moment felt like one wasted. He wasn’t sure he could keep up waiting much longer.

“Hellooo, Earth to Alexander,” Magnus laughed, snapping his fingers in front of Alec’s face, a burst of blue smoke surrounding his hand.

Alec jumped slightly, blinking rapidly. “Sorry, I guess I lost myself there a little bit.”

“Perhaps the martinis were a tad too strong?” He asked with a teasing smile. He could read his husband like a book, though, and the smile faded just as quickly as it appeared. “Are you alright?”

“Me? Technically, I’m fine.”

Magnus raised a brow. “Technically?”

“Yeah. It’s just, uh, I have something to tell you. And I’ve been waiting for the perfect moment, but those are a little hard to come by recently,” Alec sighed.

“Whatever it is, you can talk to me. I know you know that. Or, at least I hope you do.”

“Of course I know that. This is just...big.”

Magnus smirked. “I think we’ve both seen that I can—“

He was interrupted by Alec frantically waving his hands around while shaking his head. “Don’t even start.”

“You never let me have any fun,” Magnus pouted, earning an eye roll in response. Alec was too eager to get back onto the proper topic to engage in playful banter.

He pursed his lips and instinctively began fidgeting with the wedding band on his finger. It’d become a nervous habit and grounding tactic almost immediately after Magnus had given it to him before going to Edom.

Magnus watched with a concerned gaze and placed an assuring hand on Alec’s bicep, but otherwise kept to himself. He knew it was best to give silent encouragement while allowing Alec to find his words on his own.

“Do you remember how Clary left letters before she…?” Alec sighed. Sure, they weren’t the closest, but she was still a friend and it wasn’t an easy thing for him to discuss.

“Forgot about all of us?” Magnus finished with a bitter huff. He’d spent countless nights cursing the angels for making him lose yet another friend. And twice, at that.

Alec swallowed down the lump in his throat and nodded. “Yeah. Well, she left a little something extra with mine. A gift. I wanted to tell you about it so many times but every moment just felt wrong or insensitive, all things considered.”

“What kind of gift?” Magnus inquired curiously.

Momentarily dodging that question, Alec slipped off his wedding band and focused on the inscription inside.

“Aku cinta kamu, forever,” He read out before making eye contact with Magnus. His husband wore a fond expression but there was definitely some confusion lingering beneath it as well.

“What would you say if I told you we could actually have that? Forever, I mean.”

Magnus’ face fell. It was something he dreaded thinking about — the fact that he would outlive his husband, his soulmate. In that way, immortality was a curse. Every loss was a painful one but he knew losing Alec would be unbearable.

“I—We’ve talked about this before. I can’t change what I am and neither can you. Wanting for more is pointless, it will only lead to both of us getting hurt. We need to live in the here and now.”

His frown deepened as Alec’s smile grew, eyes sparkling with hope. He failed to see whatever lightness there was in this conversation.

Alec reached into his pocket and pulled out folded, slightly worn piece of paper. The amount of times he had read through it, mulling over it, was a little ridiculous.

“Not everything is so black and white, Magnus. Isn’t that what you always say? Just read this. It’ll explain everything.” There was a glimmer of hope in his eyes as he offered out the letter.

Magnus warily accepted it, immediately unfolding it to begin reading.

_Alec,_

_I know we were never the closest, but I want you to know that I truly value you as a friend. I’m eternally grateful for all of the ways you’ve helped me over the years, even when you when you weren’t sure it was the right thing to do. Thank you for giving me a chance to be apart of something so special. I loved being a Shadowhunter. It gave me a sense of purpose and a family after losing my own. I wish more than anything that I could continue being a part of this world, but I’m sure by the time you’ve found this that you’ll already know that losing my memories is the price I have to pay for all of the runes I’ve created. Everything is slowly starting to fade away as I’m writing this, so before it does, I want to give this gift to you. Nobody really gave me the rundown on Shadowhunter/Warlock wedding traditions, but at mundane weddings, there’s always gifts for the newlyweds. The rune at the bottom of this page is my gift to you and Magnus. You two are seriously one of the most perfect couples and after everything you’ve been through, you deserve an eternity together. It came to me after you’d asked Simon to turn you into a vampire, but I didn’t know what it meant until I was holding your wedding invitation the next morning. Magnus will need to enchant your stele before you draw the rune, as it requires both of you to work properly. It’s similar to the rune that bonded Jonathan and I, but this one isn’t quite as intense. It’ll bind you and Magnus together and share his immortality with you without any negative side effects. I know you must have a billion questions and I wish I could answer them all. Just trust me on this. I’ve never been able to explain my runes, but we know that they work. And like I said, the two of you deserve this._

_Good luck,_

_Clary_

Below her signature was a rune that very closely resembled the love rune, though the bottoms were curled and closed up in what was essentially an infinity symbol. Next to it, it read, _“Eternal Love rune”._

Magnus pursed his lips tightly together and blinked away the tears that threatened to spill from his eyes. Then he let out a faint laugh.

“You wanted Simon to turn you into a vampire? He’d be a terrible sire.”

Alec scoffed, rolling his eyes.

“That’s really what you want to talk about? I needed to get to Edom to save you, and Clary hadn’t thought up the alliance rune yet. It was the only viable option. I mean, sure, maybe I had some ulterior motives paired with it but…” He trailed off, gesturing to the letter Magnus was still holding. “What’s important here is Clary’s gift. So...what do you think?”

Magnus huffed out a sigh and redirected his attention back to the paper, reading through her instructions once more.

“There’s a chance this may not even work, Alexander. And then we’ll both have gotten our hopes up for nothing. I don’t know if I can bear to believe I’ve got forever with you, just for you to start aging and eventually…”

Alec frowned. “I know it’s scary and sounds almost too good to be true, but don’t we owe it to ourselves to try? Clary’s runes have always worked before.”

“I get the feeling that had more to do with Clary and her connection to the angel than anything else.”

“She wouldn’t have left this for us if it weren’t something we could do ourselves.”

Yeah, that wasn’t exactly a point that Magnus could argue.

He set the paper down on the coffee table and took both of Alec’s hands in his own. “I want nothing more than forever with you. Immortality isn’t an easy thing, though. It’d be selfish of me to jump on this opportunity without considering your feelings and future. You’ve got your family to think about.”

Alec’s frown turned into a gentle, loving smile.

“After everything, I think you deserve to be a little bit selfish, Magnus,” He teased lightly before taking a few steps closer to his husband. “I’ve been thinking about this for a long time and I know what I want. Nothing anyone says will change that. You’re the one who taught me to live for myself. Besides, you’re my husband. You’re my family now, too, and my future. I told you in Edom that I’m never leaving you again and I fully meant it. I don’t want to become someone who only lives on in stories and photographs, or a sad topic that everyone dances around at family get togethers. I want to be there for you and for our kids when we eventually have some. This is my decision. And if you don’t want to risk the rune, then I’ll just go see Simon and convince him to turn me, so…” He trailed off with a laugh.

Magnus grinned, shaking his head. “Let’s keep Simon as a last resort. A very, very last resort.”

“Does that mean you’ll give the rune a shot?” Alec asked hopefully.

“I’ll give the rune a shot,” Magnus confirmed with a nod.

Alec felt like a thousand weights had been lifted off of his shoulders. Overwhelmed with happiness and love, he cupped Magnus’ face and surged forward, connecting their lips in an excited kiss. It barely lasted more than a few seconds, though, as the couple were smiling too hard. Magnus let out a hearty laugh as they stood with their foreheads resting together.

“I love you,” Alec breathed out. “When...when do you wanna do it? The rune, I mean.”

“I love you too, angel,” Magnus chuckled, playing with the hair at the nape of Alec’s neck as he beamed up at him. “Someone is certainly eager. We can do it now, if you’d like? Today was mostly filled with booking appointments, so I’m not nearly as exhausted as usual.”

“Yes, yeah, now is perfect,” He nodded enthusiastically before pulling away from Magnus and going to grab his stele from his briefcase. When he returned to Magnus’ side, he held it out to him.

Magnus drew in a sharp breath, taking the stele from Alec. The last time he’d held one was when Alec was on the verge of death. How things had changed since then.

His eyes fell closed as he tapped into his magic, focusing on the intent. Flashes of memories with Alec played through his head like a movie. He allowed himself to get momentarily lost in their love before waving a hand over the stele, allowing his magic to flow from his palm, enchanting it. Surprisingly there was no resistance of any kind.

Once he was done, he opened his eyes and handed the stele back to his husband. His brows furrowed at the expression on his face.

“What’s wrong?”

“Nothing,” Alec assured with a shaky breath. “It’s just—your eyes. They never cease to amaze me. You’re beautiful.”

Ah, so his glamour had fallen while performing the enchantment. His cheeks heated up slightly at the compliment. Most days he still hated that part of himself, but it was refreshing to have someone who loved him so completely. And now he’d have that for the rest of time. The thought made his heart skip a beat.

Magnus cleared his throat, bringing himself back to the present. “You should probably draw the rune.”

Alec bit down on his bottom lip, suddenly feeling nervous again. “Do you think we could do it together?” His voice was soft and shy as he asked.

Immediately Magnus nodded. “Of course we can, darling. Where do you want to put it?”

“Over my heart,” Alec replied without hesitation. He’d been thinking about this a lot and really there was no better spot.

Once Magnus gave him a nod of approval, he pulled off his shirt. Obviously he’d been naked (or in this case, half-naked) around his husband more times than he could count but for some reason this moment made him feel more vulnerable than all of the others.

“You ready?” Magnus asked soft, but by looking at his expression you could tell it was meant to be more of a ‘Are you sure?’.

Alec, holding his stele in one hand, used the other to place Magnus’ on top of his. “Of course I am. I chose this. I chose you.”

Magnus would probably never get used to just how honest Alec always was with his feelings. He pressed a quick, gentle peck to his lips before looking down at the letter that lay flat on the table, taking a few moments to memorize it. When he was certain that he’d had it perfect, he began guiding their hands to draw the rune directly over Alec’s heart.

Alec winced, but the discomfort of the rune being burnt into his skin quickly faded. It was replaced with something entirely euphoric. A familiar warmth encased him, and Alec recognized it as Magnus’ magic. He sighed in contentment while his eyes slipped closed, lips curling up in a blissful smile. Magnus watched him in awe.

Once the rune was finished, it began to shimmer with blue and gold, likely a combination of Magnus’ magic and Alec’s angelic blood.

Alec’s hands fell to his side while Magnus placed one of his over the rune, the other resting in the crook of Alec’s neck.

A single tear fell slipped down Alec’s cheeks but it wasn’t from pain. He felt like he was seconds from floating away, his husbands touch the only thing anchoring him to the ground.

Suddenly the rune stopped glowing and the energy in the air shifted entirely. Alec gasped, eyes fluttering open.

“Holy shit,” He breathed out.

“Yeah,” Magnus agreed. “Did it work?”

Both of them knew it did, though. They could feel it. They felt intertwined in a sense, and like there was electricity coursing through their veins (a temporary effect of the spell).

Instead of replying, Alec kissed Magnus again. It was deep and full of passion.

When they parted, they both had teary smiles.

“You’re immortal,” Magnus laughed with disbelief.

Alec was laughing too, nodding his head. “I am. Now you’re stuck with me forever. You’ll probably regret this.”

“Never in a million years. You forget, I lived for centuries before you came along. In all of that time I never married. I never knew anyone that even comes close to you. You’re it for me, and I wouldn’t have it any other way.”

Alec swore his heart could’ve burst on the spot. “I wouldn’t have it any other way, either. I love you more than anyone and anything in the world.”

“How are we going to explain this to the others?” Magnus wondered.

“Doesn’t matter. Hell, we don’t even have to tell anyone if we don’t want to. You could glamour me to look like I’m aging and then we can portal off to a remote island for the rest of eternity when everyone thinks I’ve kicked the bucket,” He joked.

Magnus snorted. “I’m not entirely sure that would work.”

“Probably not. Eh, we’ll figure it out. We’ve got time. All the time the world has to offer,” Alec pointed out with a cheesy grin.

Magnus couldn’t help but roll his eyes, playfully shoving his husbands shoulder.

“Alright. If you’re done dropping life changing bombshells on me, I think I’ll conjure us up some dinner. I’m starving. What do you say?”

“No more life changing bombshells, Shadowhunters honor.” Alec had a hand raised as if he were performing some kind of mundane oath swearing. “And dinner sounds perfect.”

With a grand hand flourish and snap of his fingers, a romantic arrangement appeared on their dining table along with a spread of food from one of their favorite restaurants in Paris.

“Bon appetit, Mr. Lightwood-Bane,” Magnus said with a wink.

Now it was Alec’s turn to roll his eyes. “You’re a dork. Come on, let’s eat.”

**Author's Note:**

> thank you so so much for reading! again, i really hope that you guys enjoyed!
> 
> i'd love to hear your thoughts & stuff so i'm gonna shamelessly plug my twitter @heroicgay!


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